Question

For 5 cups of milk you need 4 cups of oatmeal, how many cups of oatmeal will be needed for 1 cup of milk?

Answer 1

The ratio milk-oatmeal has to stay the same; then, if x represents the cups of oatmeal we need for 1 cup of milk, we get:

$\begin{gathered} \frac{5}{4}=\frac{1}{x} \\ \Rightarrow x=\frac{4\cdot1}{5}=\frac{4}{5}=0.8 \end{gathered}$

The answer is 4/5 or 0.8 cups of oatmeal